PHOTOGRAMMETRIC TECHNIQUES FOR MEASUREMENTS IN WOODWORKING 
INDUSTRY 
V. Knyaz ^ *, Yu. Visilter, S. Zheltov 
? State Research Institute for Aviation System (GosNIIAS), 7, Victorenko str., Moscow, Russia 
Knyaz@gosniias.ru 
Commission V, WG V/1 
KEY WORDS: Close-range photogrammetry, calibration, industry, measurement, forestry, image processing. 
ABSTRACT: 
Accurate measurement of wood volume is a very important task at each stage of woodworking process beginning with estimation of 
volume of cut trees and finishing with determining the volume of resulting product. In most cases, current technology of 
measurement is based on inexact manual procedures and gives rather rough data. To introduce a new measurement technology in 
woodworking industry 3D imaging techniques are developed for two general stages of woodworking: for volume estimation of tree 
packages coming to logging enterprise and for volume determination of a log moving on a conveyor belt. 
The system for cut tree packages estimation is based on sterco image acquisition of the front view of the tree package and calculation 
of the area of log cuts. The developed methods for cuts measurements are discussed. For log volume determination during conveyor 
wood processing a technique based on moving log image acquisition in stripe light is developed. It allows generating a 3D model of 
the log which is used for volume estimation. 
The paper describes the developed methods of 3D measurements, outlines of the hardware used for image acquisition and the 
software realized the developed algorithms, gives the productivity and precision characteristics of the system. 
1. INTRODUCTION 
The problem of accurate measurements in logging and 
woodworking industry is very important and actual. 3D imaging 
technique gives wide opportunities for solving this problem and 
could be applied at any stage of wood processing. One of the 
processes, which demands for accurate and fast performing, is 
determination of cut trees package volume carried by the truck 
(Fig.1.). In most cases measurements requires an operator as a 
key element. The operator measures the width and height of 
front area with a ruler and manually writes the measured values 
into notebook. Then the volume of the package is estimated 
using empirical equation. The procedure seems to have low 
accuracy, low productivity and good background for man-made 
errors. 
  
Figure 1. Cut trees package to be measured 
  
The proposed system for cut tree packages estimation includes a 
set of CCD video cameras, PC equipped with frame grabber and 
original software for image processing and 3D measurements. 
Two methods for measuring are developed and discussed. The 
first one is based on stereo matching of the tree package images 
and model based tree cuts extraction. The second approach uses 
image orthotranformation into front plane to obtain rectified 
image which is more convenient for processing. This technique 
allows processing transformed image for ellipsoidal shapes 
detection and calculating their area. The developed algorithms 
for shape extraction provide high robustness. They are based on 
modified Hough transformation technique and computational 
geometry algorithms for convex hull generation. 
Another problem which requires automated non-contact 
measurement solution is volume determination of a log moving 
on conveyor belt. The technique for a log volume determination 
is based on lighting the log by bright stripe during its movement 
along a conveyor. It allows real-time calculating a set of the 
log’s profiles with frame rate frequency and to generate a 3D 
model of the log which is used for volume estimation. Special 
cameras calibration procedure is developed for providing metric 
characteristics of the system. 
The image-based 3D-measurement system is proposed as an 
alternative for manual measurement. The main requirements to 
the developed system are following: 
e high precision of 3D measurements 
e high productivity - capability of fast measurements 
e support of on-line and off-line mode 
e support of automated measuring mode 
* V.Knyaz. Tel. 7-095-1573127, Fax: 7-095-1573900, e-mail: Knyaz@gosniias.ru 
    
    
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